Howto process multivariate time series given as multiline, multirow *.csv files with Apache Pig?

0
votes

I need to process multivariate time series given as multiline, multirow *.csv files with Apache Pig. I am trying to use a custom UDF (EvalFunc) to solve my problem. However, all Loaders I tried (except org.apache.pig.impl.io.ReadToEndLoader which I do not get to work) to load data in my csv-files and pass it to the UDF return one line of the file as one record. What I need is, however one column (or the content of the complete file) to be able to process a complete time series. Processing one value is obviously useless because I need longer sequences of values...

The data in the csv-files looks like this (30 columns, 1st is a datetime, all others are double values, here 3 sample lines):

17.06.2013 00:00:00;427;-13.793273;2.885583;-0.074701;209.790688;233.118828;1.411723;329.099170;331.554919;0.077026;0.485670;0.691253;2.847106;297.912382;50.000000;0.000000;0.012599;1.161726;0.023110;0.952259;0.024673;2.304819;0.027350;0.671688;0.025068;0.091313;0.026113;0.271128;0.032320;0 17.06.2013 00:00:01;430;-13.879651;3.137179;-0.067678;209.796500;233.141233;1.411920;329.176863;330.910693;0.071084;0.365037;0.564816;2.837506;293.418550;50.000000;0.000000;0.014108;1.159334;0.020250;0.954318;0.022934;2.294808;0.028274;0.668540;0.020850;0.093157;0.027120;0.265855;0.033370;0 17.06.2013 00:00:02;451;-15.080651;3.397742;-0.078467;209.781511;233.117081;1.410744;328.868437;330.494671;0.076037;0.358719;0.544694;2.841955;288.345883;50.000000;0.000000;0.017203;1.158976;0.022345;0.959076;0.018688;2.298611;0.027253;0.665095;0.025332;0.099996;0.023892;0.271983;0.024882;0

Has anyone an idea how I could process this as 29 time series? Thanks in advance!

1
csvhadoopapache-pigtime-series

1 Answers

0
votes

What do you want to achieve?

If you want to read all rows in all files as a single record, this can work:

a = LOAD '...' USING PigStorage(';') as <schema> ;
b = GROUP a ALL;

b will contain all the rows in a bag.

If you want to read each CSV file as a single record, this can work:

a = LOAD '...' USING PigStorage(';','tagsource') as <schema> ;
b = GROUP a BY $0; --$0 is the filename

b will contain all the rows per file in a bag.